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a7042ddbe4
Use wrappers to call the kernal in bank 15 instead of implementing kernal functionality within the cc65 libs (eats performance but is much smaller and simpler). Improved startup/shutdown code allows a return to the system bank without calling the BASIC cold start vector. git-svn-id: svn://svn.cc65.org/cc65/trunk@2793 b7a2c559-68d2-44c3-8de9-860c34a00d81
44 lines
577 B
ArmAsm
44 lines
577 B
ArmAsm
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; Ullrich von Bassewitz, 22.09.1998
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;
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; void clrscr (void);
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;
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.export _clrscr
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.import plot
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.import CURS_X: zp, CURS_Y: zp, CharPtr: zp
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.include "cbm610.inc"
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.proc _clrscr
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lda #0
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sta CURS_X
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sta CURS_Y
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jsr plot ; Set cursor to top left corner
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lda IndReg
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pha
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lda #$0F
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sta IndReg ; Switch to the system bank
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ldx #8
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ldy #$00
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lda #$20 ; Screencode for blank
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L1: sta (CharPtr),y
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iny
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bne L1
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inc CharPtr+1
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dex
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bne L1
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pla
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sta IndReg ; Restore old indirect segment
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jmp plot ; Set screen pointer again
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.endproc
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